1. Field of the Invention
The present invention relates generally to controllers and methods therefor for maintaining energy consumption at a predetermined value while minimizing inconvenience to users thereof, and more particularly, to an energy controller and method therefor designed for use in conventional residential housing minimizing noticable heat loss to the various rooms therein.
2. Description of the Prior Art
Power supply companies have traditionally billed industrial users based upon a "demand" billing rate. Such a rate structure is desirable since the power supply company must be capable of meeting peak supply demands by its various industrial users. Therefore, it is highly desirable to bill industrial users based upon their highest demand for generally a 15 minute interval during a given month. While industry has responded with a variety of approaches to substantially reduce peak demand levels during a given month through use of a variety of energy allocation devices, none of these prior art approaches have been found suitable for private residential use.
Power supply companies have traditionally billed residential consumers based upon what is commonly called the "declining block rate" basis. This "rate" basis for computing power consumption is based upon the concept that the residential user should pay for the power actually used. The philosophy behind this approach being that most consumers live within a predetermined amount of average power consumption so that the power supply company can properly allocate the power requirements to the residential community.
Power supply companies, however, in various states have started to adopt the "demand" rate structure for residential use as a way to lower the cost of electricity to homeowners.
One prior art approach adapted for use by homeowners using the "demand" rate structure is disclosed in "Energy Demand Controlling and Method Therefor", U.S. Pat. No. 4,090,062, issued May 16, 1978 wherein the inventors set forth an approach for providing a low-cost approach for energy priority and allocation in order to prevent peak energy usage from occurring. In that prior art approach, the inventors set forth a new and novel system for the allocation of energy in the various heating zones or rooms within the house by sequentially turning on heaters in each zone for a predetermined length of time, usually one second, thereby preventing the simultaneous activation of all heaters in all zones at the same time. The energy demand controller set forth in this prior art approach turns ON a first heating zone for only one second and continues to cycle through the remaining heating zones until it returns back to the first zone and turns that zone ON for an additional second. This cycling process repeats. In the event that the inhabitant of the house or building desires to use an appliance, a special override feature is provided so that while the appliance is being used, no cyclic heating in the zones occurs. Furthermore, the energy demand controller set forth in the above application further functioned when the temperature in each of the zones fell below a predetermined low value to activate the heater within that zone on a fulltime basis until the temperature was raised to a predetermined range. Whenever a given number of zones required such fulltime heating, the energy controller prevented any other appliance from being activated until the room temperature was brought up to within acceptable ranges.
Prior to the filing of this application, the inventors effectuated a patentability investigation to be performed. The results of that investigation are as follows:
______________________________________ Inventor Pat. No. Date ______________________________________ Williams 3,296,452 Jan. 3, 1967 Polenz 3,602,703 Aug. 31, 1971 Dillon, et al 3,652,838 March 28, 1972 Stevenson 3,906,242 Sept. 16, 1975 Owenby, Jr. 3,937,978 Feb. 10, 1976 ______________________________________
The 1975 patent issued to Stevenson, U.S. Pat. No. 3,906,242, uses a load sensor to detect the electrical load being delivered to hotels and motels, colleges and schools, public housing and dorms, apartments, etc. Stevenson seeks to lower the peak electrical energy demand on a central electrical distribution network to specifically alleviate the occurrence of a power emergency. In accomplishing his goal, Stevenson senses the approach of an excessive demand peak and commences remotely, via radio signals, to disconnect simultaneously a number of interruptible loads such as hot water heaters. Whether or not such loads are disconnected is based upon energy consumption profiles predicted from past statistical records for such loads.
The 1967 patent to Williams, U.S. Pat. No. 3,296,452, seeks to efficiently utilize energy consumption during the demand interval. Williams seeks to have all loads operating at 100% of a predetermined demand interval value but not to exceed that amount for maximum efficiency. To accomplish this goal, Williams utilizes a differentially-responsive device having a first input produced at predetermined intervals, a second input from a variable quantity, a first pattern for establishing a first predetermined limit for the variable quantity, a second pattern operative with the first input for establishing a second predetermined limit pattern for a portion of each of the predetermined intervals, and a differential means receiving the first input, the first pattern, and the second pattern for responding to the difference between the input from the variable quantity in the sum of the limit patterns for each of the intervals. The circuit for accomplishing this is shown in FIG. 3 of Williams.
The 1976 patent to Owenby, Jr., U.S. Pat. No. 3,937,978, is adapted for hotels, motels, etc. in order to prevent under-voltage or freezing conditions from arising in rooms having occupants located therein. The Owenby approach utilizes a remote control system having various switches for controlling the electrical power supplied to various loads, electrical sensors for providing a signal corresponding to the variations of the electrical power from a prescribed value, and a restart circuit for receiving the signal from the sensor and having a timer for producing a timing signal representative of the time the signal from the electrical signal exists, a plurality of outputs coupled with the switches and responsive to the signal from the sensor for interrupting the power to the load, and a sequencer responsive to the timer to sequentially operate the output whereby power is returned to the load sequentially.
The patents issued to Dillon, U.S. Pat. No. 3,652,838 and to Polenz, U.S. Pat. No. 3,602,703 relate to complicated electrical priority control systems adaptable for the industrial environment.
None of the above approaches resulting from the search are related to nor solve the residential "demand" rate situation. The closest of the prior art approaches to solving this problem is presented by the inventors' own prior art system. The present invention, however, is new and novel over the inventors' prior energy demand controller. The present invention allows the user to preselect a level of power consumption thereby enabling the inhabitant of the house or building to predetermine his monthly bill. The preselected value of energy consumption is continually compared to the instantaneous power consumption delivered to the residential building. Whenever the instantaneous power consumption exceeds the predetermined level, one or a plurality of zone heaters are turned OFF within the building for a predetermined time interval, such as 16 seconds. Enough zones are turned OFF to cause the instantaneous power to be less than the desired power. At the end of the predetermined time period, the deactivated zone heaters are turned back ON and if the instantaneous power consumption still exceeds the predetermined value, other zone heaters are turned OFF in cyclical fashion for another 16 second period. This cycling continues until the instantaneous power no longer exceeds the predetermined value. Minimal heat loss occurs in the various rooms due to the thermal lag of the walls of the building while the heat in the respective zones is turned off. If all of the heaters are turned off in any given 16 second period, and the instantaneous power is greater than the power limit, then the power to the hot water heater is turned off. If the instantaneous power still exceeds the preselected power limit, an audible alarm sounds informing the inhabitant of the house to deactivate appliances, etc. to maintain the instantaneous power below the predetermined amount or to raise the predetermined level of use. None of the above prior art approaches set forth the novel approach of the present invention as set forth above.